湿热处理温度对多孔淀粉理化性质的影响

目的:研究湿热处理温度对多孔淀粉理化性质的影响。方法:将湿热处理温度分别控制在110、115和120℃,在水分含量为15%条件下湿热处理1 h,研究在该条件下湿热处理对多孔淀粉结构和性质的影响。结果:在水浴温度为85℃条件下多孔淀粉溶解度随湿热处理温度的增加而增加,膨胀度随着湿热处理温度的增加而下降;多孔淀粉吸油率随湿热处理温度的升高而增加;多孔淀粉糊的透光率随湿热处理温度的升高而下降,淀粉糊冻融稳定性、起始糊化温度和热糊稳定性随着湿热处理温度的升高而增强,糊化峰值粘度随湿热处理温度的升高而降低;湿热处理温度对多孔淀粉的结晶结构影响不大,多孔淀粉依然为A型结晶结构,随处理温度的升高其结晶度略有降低;当湿热处理温度为115℃时,其抗性淀粉含量最高,达27.67%。结论:湿热处理温度对多孔淀粉理化性质有明显影响,且随着湿热处理温度的不同存在差异性。      

Effect of microwave heat/moisture treatment on physicochemical properties of Canna edulis Ker starch

BACKGROUND: Microwave heat/moisture treatment (MWT) is being used increasingly in food processing, but very little research has been carried out on its effect on tuber starches. In this study, Canna edulis Ker tuber starch was subjected to MWT with moisture contents ranging from 20 to 45% (w/w), and the effects of MWT on the physicochemical properties of the starch, including the extent of amylose leaching, enzymatic digestibility, X‐ray diffraction (XRD) and differential scanning calorimetry (DSC) characteristics, were determined. RESULTS: In the process of MWT, temperature exhibited a positive correlation with microwave power and moisture content. When amylose leaching was used as an index, a moisture content of 40%, a treatment time of 15 min and a microwave power of 800 W were found to be the optimal conditions for MWT of C. edulis starch. The enzymatic digestibility changed under different treatment conditions. Furthermore, XRD measurements revealed a change in crystalline structure from type B to type A and an increased degree of crystallinity. Thermal (DSC) studies showed higher values of T_o, T_p and T_c of endothermic peaks, and exothermic peaks were also observed. CONCLUSION: MWT increased the degree of crystallinity, resulting in more resistant fractions in C. edulis starch, which will be beneficial to human health. Copyright © 2009 Society of Chemical Industry     

韧化及湿热处理对大米淀粉理化特性和微观结构的影响

针对目前鲜有的韧化和湿热处理对大米淀粉改性效果的对比研究,本文采用韧化及湿热处理大米淀粉,对比分析韧化处理和湿热处理对大米淀粉溶解度、膨胀度、消化性、糊化特性、微观结构及晶体结构的影响。结果显示,经韧化处理后,淀粉溶解度、膨胀度及还原糖释放率上升,凝胶强度升高,淀粉更易于糊化,但热稳定性降低;而经湿热处理后,淀粉溶解度、膨胀度和还原糖释放率明显降低,糊化凝胶强度减小,且更难于糊化,但淀粉的热稳定性提高,回生性降低。X-衍射分析表明,处理后大米淀粉依然为\     

湿热处理对板栗淀粉结构及理化性质的影响

以板栗淀粉为对象,采用湿热处理方法对板栗淀粉进行物理改性,通过控制湿热处理的时间(2~18 h)、温度(80~120℃)、含水量(10%~30%),制得不同处理条件下的板栗淀粉。随着湿热处理程度的加强,板栗淀粉的溶解度、膨胀度均减小,其中,处理温度的影响较大;湿热处理后板栗淀粉的透光率下降;板栗原淀粉颗粒的表面光滑,多数呈椭圆形、梨形等;湿热处理后,淀粉颗粒大部分保持原状,但部分颗粒表面出现轻微的凹陷和破损;X-射线衍射图谱显示虽然淀粉结晶型仍为C型,但淀粉颗粒内部有新的结构出现。     

机械活化处理对绿豆淀粉理化性质的影响

为探究球磨机械活化处理对绿豆淀粉理化性质的影响,对机械活化后绿豆淀粉的颗粒形貌和粒度分布进行观察,并进一步对其热力学性质、糊化性质、溶解度、膨胀度、持水能力和冻融稳定性等理化性质进行测定。结果表明,淀粉颗粒形貌发生了改变,表面变得粗糙不光滑,形状不规则,淀粉颗粒粒度分布范围为2～200 μm,70%以上分布在20～75 μm区间,粒度中位径增大到43.09 μm,热焓值降低至2.32 J/g,糊化温度显著降低,衰减值及回生值分别为原淀粉的1/30和1/31,微细化绿豆淀粉具有较好的热糊和冷糊稳定性,溶解度和膨胀度随着温度的升高而增大,持水能力和冻融稳定性为原淀粉的3.2倍和2.0倍。     

抗性淀粉对淀粉理化性质和酶解速率的影响

将抗性淀粉和蜡质玉米淀粉按不同的比例混匀制成复配粉,研究不同含量抗性淀粉对复配粉的膨胀度、溶解度、糊化特性和酶解速率的影响。结果表明:随抗性淀粉含量增加,复配粉溶解度降低,膨胀度增大,酶解速率逐渐降低。快速黏度分析仪(RVA)分析表明:抗性淀粉所占比例增加,复配粉的糊化温度逐渐升高,抗性淀粉含量为60%时,糊化温度达到最高,为75.25℃,而峰值黏度、谷值黏度、末值黏度、衰减值和回生值逐渐下降,抗性淀粉含量为100%时,复配粉的峰值黏度、谷值黏度、末值黏度均达到最低。     

Effect of heat moisture treatment on resistant starch content among carbohydrate sources: a meta-analysis

Resistant starch (RS) can be generated through heat moisture treatment (HMT). The HMT was conducted by modifying starch using different ratio of moisture content, high temperature and heating time. A number of studies showed that the effects of HMT on RS contents in cereals, pulses, tubers and fruits were inconsistent. This study aimed to analyse the impact of HMT on RS level in various carbohydrate sources through a meta-analysis approach. Study selection was conducted with the PRISMA method. There were 21 relevant studies and 67 data used for meta-analysis. The database was analysed by using Hedges’ d. The results showed that there was a significant impact of HMT on RS level of cereals, especially wheat. The highest increase in RS levels for various carbohydrate sources in starch was influenced by the interaction of treatment between water content at 15 ≤ x < 25%, heating time at 0.25 < x ≤ 6 h and temperature at 120 ≤ x ≤ 130 °C.     

湿热处理对大米淀粉理化性质及其米线品质的影响

以大米淀粉为原料,研究湿热处理对大米淀粉理化性质以及米线品质的影响。结果表明:与未处理大米淀粉相比,湿热处理后,大米淀粉的热学特性中T_0、T_P、T_C、T_C_T0、ΔH均增大;淀粉晶型仍为A型,结晶度增加4.14%;淀粉溶解率和膨润力显著降低,直链淀粉含量显著升高;淀粉糊化黏度、衰减值和回生值明显降低;淀粉凝胶硬度、弹性和耐咀嚼性增强;淀粉白度由89.7降低至80.3;添加20%湿热处理大米淀粉制作的米线感官品质和质构特性得到显著改善,断条率和蒸煮损失率分别降低5.67%,10.13%;大米淀粉溶解率、膨润力、溶解率、凝胶特性和糊化特性可有效预测米线品质。     

Effect of moisture content on selected physicochemical properties of two commercial hen egg white powders

After short-term storage at 23 °C, selected physicochemical properties of two hen egg white powders (with and without hydrolysis) were studied. Overall, the effect of moisture content on physicochemical properties of Hydrolysed Egg White powder (HEW) was more severe than those of Dried Egg White powder (DEW). The denaturation temperature (T_d) and its enthalpy change (ΔH_d) of ovalbumin in DEW followed an exponential model, as well as the T_d of HEW. The Gordon-Taylor equation modelled well the glass transition temperatures (T_g) of HEW and DEW. The Guggenheim-Anderson-de Boer (GAB) model fitted well to the type II moisture sorption isotherm. At the critical moisture content (12.0%, dry basis), compared with DEW, the colour of HEW began to darken dramatically and its hardness started to change significantly. These changes were closely related to the inherent characteristics of the two products. The mechanisms relevant to these physicochemical changes were discussed.     

逆研磨对木薯淀粉理化性质的影响

采用贝利粉碎机对木薯淀粉进行机械活化,研究了逆研磨对木薯淀粉理化性质的影响。结果表明,逆研磨后,颗粒粒径变化很小,团聚颗粒更多,结晶结构无变化,溶解度增大,膨胀度、表观粘度减小,透明度变化不大,剪切稀化程度降低,Brabender黏度曲线由B型变为D型。     

Effects of moisture content and drying temperature on the physicochemical properties of ostrich jerky

The objective of this study was to investigate the influence of temperature (50, 60, and 70 degrees C) and moisture content (18, 21, and 24%) on the quality ofjerky products from ostrich meat. The jerky products were evaluated by physicochemical and sensory methods. The tensile strength of the samples prepared to 24% w.b. moisture content at 50 degrees C was lowest (p < 0.05; 124 N) while those prepared under other conditions were in the range of 208-268 N (p > 0.05). The water activity of the jerky products was 0.51-0.72, and significant influence of drying temperature on protein solubility was also observed, but the samples dried at the same temperature had similar levels of soluble protein (p > 0.05) regardless of moisture content of samples. The pH of the samples dried at 50 degrees C and 60 degrees C showed little change in different moisture content, but samples dried at 70 degrees C tended to affect the pH by moisture content. Hunter a-values showed a predominantly increasing trend in all moisture levels as the heating temperature increased. The jerky product prepared to 24% w.b. moisture content at 60 degrees C showed the best sensory overall acceptability.     

球磨处理对大米淀粉理化性质的影响

为了扩大大米淀粉的应用范围,对其进行球磨处理,并分析不同转速条件下球磨处理对大米淀粉理化性质的影响。结果表明,随着球磨转速的加大,大米淀粉颗粒形态被破坏的程度越大;球磨能使大米淀粉分子链发生断裂,导致还原糖含量增加;大米淀粉的冷水溶解度与球磨转速正相关,球磨处理程度较高的大米淀粉几乎冷水可溶;球磨处理使大米淀粉的成糊温度、峰值黏度和最终黏度降低,淀粉糊的稳定性提高。     

挤压对小米淀粉理化特性的影响

采用双螺杆挤压机在5个套筒温度和物料水分水平下对小米进行挤压膨化,然后测定产品中淀粉的理化特性。结果表明:与物料水分相比套筒温度对小米淀粉糊化度的影响较大,而对水溶性糖含量的影响相反。V区温度从165℃升至180℃时糊化度明显降低,物料水分从15%升至21%时水溶性糖含量降低。与套筒温度相比物料水分对特征黏度影响较大,其值在单位机械能耗(SME)大于420W·h/kg时不再随SME增大而进一步降低。RVA测定结果也显示挤压导致淀粉糊化和降解;RVA黏度随套筒温度升高而升高,直至195℃;随物料水分含量升高而升高,直至21%。     

Effect of cross-linking on the physicochemical and physiological properties of corn starch

Corn starch was chemically modified by cross-linking with STMP/STPP (99:1. w/w) and the physicochemical and physiological properties (in vitro and in vivo) of the cross-linked corn starch were investigated as a function of the degree of cross-linking. Cross-linking decreased the solubility, swelling factor, and paste clarity of corn starch. While the swelling factor was highly correlated with the degree of cross-linking (R² = 0.878), the X-ray diffraction patterns did not show any significant alteration in the crystallinity of corn starch. It was shown by SEM measurement that a black zone was observed on the surface of crossed-linked starch granules, which did not occur with native starch. When mice were fed the diets containing the corn starch with low (CLCS-5) and high (CLCS-12) degree of cross-linking (51.3 and 99.1%, respectively), significant effects on the final body weight, weight gain as well as perirenal weight of the mice (p < 0.05) were observed. Also, significant decreases in total lipid, triglyceride, and total cholesterol concentrations in serum were detected in CLCS-5 and CLCS-12 groups (p < 0.05). While total lipid level in the liver decreased with increasing degree of cross-linking, the triglyceride level was not affected by the supplementation with both of CLCS-5 and CLCS-12 corn starch samples.     

球磨对绿豆淀粉颗粒形态和理化性质的影响

采用行星式球磨机对绿豆淀粉进行改性研究,以球磨时间为控制变量,对比球磨0、1、2、4、6h时绿豆淀粉颗粒形态和淀粉糊理化性质的变化.结果表明,球磨处理后绿豆淀粉颗粒表面出现凹痕,表皮变皱逐渐破裂,随时间的增加颗粒变得扁平并有抱团现象,偏光十字逐渐模糊直至消失;随球磨时间的延长,损伤淀粉和直链淀粉含量增加,淀粉糊溶解度、透明度和析水率均显著增大,淀粉糊峰值黏度、谷值黏度、最终黏度、回生值和衰减值均呈下降趋势.     

Effect of ozone treatment on physicochemical properties of waxy rice flour and waxy rice starch

The effect of ozone treatment on physicochemical properties of waxy rice flour and waxy rice starch was investigated. Results showed that ozone treatment increased the pasting viscosity of waxy rice flour. Compared with untreated waxy rice flour, the peak viscosities of waxy rice flour for 0.5, 1 and 2 h of ozone treatments were increased by 27.4%, 32.8% and 45.5%, respectively. The alpha‐amylase in waxy rice flour was inactivated during the treatment. The gelatinisation temperature and enthalpy of waxy rice flour were kept unchanged after the treatment. For waxy rice starch, pasting viscosity, swelling power and molecular weight were increased after 0.5 h of treatment, but decreased as treatment time extended. The ozone treatment decreased gelatinisation temperature and enthalpy of waxy rice starch.